JAVASCRIPT

js iterate array index

for (let [index, val] of array.entries()) {
        // your code goes here    
}

js iterate match indexes

const targetText = ''
let reg = /e(.*?)e/g;
let result;

while((result = reg.exec(targetText)) !== null) {
  	// result: ['', '', '', index: 210, input: '[targetText]', groups: undefined]
    doSomethingWith(result);
}

JS iterate over an array

const beatles = ["paul", "john", "ringo", "george"];

beatles.forEach((beatle) => {
  console.log(beatle.toUpperCase());
});

JS iterate over an array

const beatles = [ "john", "paul", "ringo", "george"];

beatles.forEach((beatle) => {
  console.log(beatle);
});